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Biomedical subjects

Z Onouchi

Publications and source records attributed to Z Onouchi.

At least 37 records · Page 2Linked to original sources
PubMed1993

Transformation of coronary artery aneurysm to obstructive lesion and the role of collateral vessels in myocardial perfusion in patients with Kawasaki disease.

OBJECTIVES: The aim of this study was to examine the transformation of coronary artery aneurysms to obstructive lesions and to assess the role of collateral vessels in patients with Kawasaki disease. BACKGROUND: Coronary artery aneurysms, especially giant aneurysms, are known to become obstructive lesions in patients with Kawasaki disease. However, the process of transformation is not yet clear. METHODS: Thirty patients (average age 9.9 years) with obstructive lesions secondary to Kawasaki disease underwent repeated coronary artery angiography and thallium myocardial scintigraphy over a mean period of 7.7 years after the acute onset of Kawasaki disease. RESULTS: In the 27 patients who were enrolled in the acute phase of the disease because of coronary artery aneurysms, the later transformation to obstructive lesions was not significantly different between the 61 large and 6 medium-sized aneurysms. Obstructive transformation of aneurysms was more rapid in the right than in the left coronary artery (p < 0.001). From the last coronary angiogram obtained, the obstructive lesions were classified as localized stenosis > 90% in 10 vessels, occlusions in 6 vessels and segmental stenosis in 26 vessels. Both localized and segmental stenosis occurred significantly more often in the left anterior descending and the right coronary artery than in other vessels (p < 0.05). The incidence of collateral vessels was significantly correlated with a younger age at onset of Kawasaki disease, especially in patients with segmental stenosis (p < 0.001). Collateral vessels did not develop in the presence of localized stenosis regardless of the occurrence of myocardial ischemia. All occluded vessels had collateral development regardless of the presence of myocardial infarction. CONCLUSIONS: The treatment of localized stenosis may play an important role in preventing myocardial infarction in the chronic phase of Kawasaki disease.

Acute Disease↗
PubMed1993

Pulmonary hypertension as a fatal complication of extrahepatic portal hypertension.

Pulmonary hypertension is an uncommon complication of portal hypertension seen in cirrhotic as well as noncirrhotic patients. We report a 10-year-old girl who presented with extrahepatic portal hypertension and pulmonary hypertension in the absence of intrinsic liver disease. Further investigations revealed high serum concentrations of prostaglandin F2 alpha, thromboxane B2 in the inferior vena cava, and angiotensin I in the inferior vena cava and right ventricle. The increased levels of these vasoconstrictive substances strongly suggest that the possible mechanism for the pulmonary hypertension in such patients with extrahepatic portal hypertension include shunting of vasoactive agents from the splanchnic circulation to the pulmonary vascular bed.

Angiotensin I↗
PubMed1993

[Myocardial energy metabolism in children: age-dependent myocardial utilization patterns of oxygen and energy substrates].

Myocardial utilization patterns of oxygen, lactate, pyruvate, glucose and free fatty acid (FFA) were evaluated in 65 children aged 7 months to 18 years (mean: 7.9 years) without organic cardiac lesions by coronary sinus catheterization via the femoral vein. Myocardial oxygen uptake was positively correlated with age. Myocardial oxygen uptake per unit left ventricular mass and the oxygen extraction rate were negatively correlated with age. The oxygen saturation of coronary sinus blood was significantly lower in younger children. The myocardial lactate and pyruvate extraction rates increased with age, but there was no correlation between lactate or pyruvate uptake and age. The myocardial FFA extraction rate increased with age and the FFA uptake per unit left ventricular mass was positively correlated with age. There was no significant relationship between myocardial glucose utilization and age. Coronary sinus blood flow per unit left ventricular mass was negatively correlated with age. These results indicate that younger children have significantly higher demands for coronary blood flow per unit ventricular mass, significantly higher utilization of oxygen, and significantly lower utilization of FFA, with the highest energy production rates.

Adolescent↗
PubMed1992

Postoperative management of children with biliary atresia and heart failure.

The postoperative course in two children with extrahepatic biliary atresia and cardiovascular disease was reviewed and the correlation between biliary drainage and cardiac function was analyzed. Both patients obtained satisfactory biliary drainage after Kasai's hepatic portoenterostomy. One patient developed heart failure postoperatively due to severe viral myocarditis. This child's total serum bilirubin concentration remained elevated for eight months, despite adequate bilirubin excretion, until her cardiac function returned to normal. Another patient died of cardiac failure due to congenital heart disease 83 days after Kasai's operation, but his postoperative biliary drainage was satisfactory as long as cardiac function remained compensated. In both cases, fluid intake was restricted severely (30 to 70 ml/kg body weight/day), as titrated by echocardiographic assessment of cardiac function, but biliary excretion was satisfactory as long as the cardiac fractional shortening ratio was greater than 30% and the ejection fraction was greater than 55%. This suggests that cardiac decompensation affects postoperative biliary excretion in patients with biliary atresia; however, with careful medical management satisfactory biliary drainage can be achieved even in patients with severe heart diseases.

Biliary Atresia↗
PubMed1992

Quantitative histological analysis of the human sinoatrial node during growth and aging.

BACKGROUND: Fibrosis or fatty infiltration of the human sinoatrial (SA) node is generally believed to represent replacement of the SA nodal cells by connective tissue. Quantitative analysis, however, has not been performed precisely to validate the interpretation of such histological changes. METHODS AND RESULTS: The actual volume of the SA node and its components were calculated according to the sum of the pixel number representing the colors of SA nodal cells and connective tissue in serial sections using a digital color image analyzer. Average volume occupied by the total SA nodal cells in adolescents and adults (n = 7) was 3.55 +/- 0.45 mm3, which was 2.4 times greater than that in infants (n = 3). The rate of increase was smaller than that of the total SA node (4.2 times, 16.68 +/- 2.56 mm3 in adolescents and adults). The considerable discrepancy in the growth ratio between the SA nodal cells and the total SA node resulted from an increase in the volume of connective tissue (7.4 times). In the elderly (n = 9), the volume of total SA node and SA nodal cells actually decreased (13.10 +/- 1.85 mm3 and 2.18 +/- 0.44 mm3), whereas that of fibrous connective tissue remained unchanged. Constant DNA ploidy patterns of SA nodal cells determined by cytofluorometry indicated that SA nodal cells never synthesize DNA during growth. CONCLUSIONS: Until adulthood, the actual volume of SA nodal cells does not decrease, although the increase in volume ratio of the interstitial tissue to the total SA node has merely given a false impression of involution of SA nodal cells. Atrophy of SA nodal cells, however, occurs during aging together with reduction of the SA node and/or infiltration of fatty tissue.

Adolescent↗
PubMed1992

Percutaneous transluminal coronary angioplasty in a patient with Kawasaki disease. A case report of an unsuccessful angioplasty.

A 13-year-old boy with severe coronary stenosis due to Kawasaki disease underwent percutaneous transluminal coronary angioplasty (PTCA). The guide wire and the balloon catheter easily passed through the stenosis in the left anterior descending artery. However, effective dilatation could not be achieved even when the balloon size was increased to 2.5 mm in diameter. We discontinued further inflation of the balloon because serious resistance was encountered on withdrawal of the balloon catheter. In patients with Kawasaki disease, the value of PTCA as a treatment for coronary stenosis is questionable.

Adolescent↗
PubMed1992

[Effects of isosorbide dinitrate on coronary and systemic circulation in children: comparison with dipyridamole].

The effects of isosorbide dinitrate (ISDN) on the coronary and systemic circulation were evaluated in comparison with the effects of dipyridamole (DP) in 8 children with histories of Kawasaki disease and angiographically normal coronary arteries. ISDN (100 micrograms/kg) was administered as an intracoronary injection. DP was administered intravenously at the rate of 0.56 mg/kg for 4 min. In the coronary circulation, DP induced a significant reduction of the afterload, resulting in an increase in cardiac output. However, the pulmonary artery pressure, pulmonary capillary wedge pressure and left ventricular end-diastolic pressure, which are related to the preload, were significantly reduced one min after the ISDN injection. The systolic blood pressure was reduced, while the heart rate was increased. The cardiac output, pressure-rate product or systemic vascular resistance showed no significant change. The systolic work index, however, was significantly reduced. In the coronary circulation, DP significantly increased the coronary sinus blood flow due to dilatation of the resistant vessels. However, ISDN significantly dilated the conductant vessels by 4.0 to 12.9% in diameter. There was, however, no change in the coronary blood flow, coronary perfusion pressure nor coronary vascular resistance. The grade of dilatation of the coronary vessels caused by ISDN was lower in children than in adults.

Adolescent↗
PubMed1991

Asymptomatic myocardial infarction in Kawasaki disease: long-term prognosis.

Eight patients with Kawasaki disease who had sustained asymptomatic myocardial infarction 8-15 years ago (mean, 13.1 years) were reexamined by various noninvasive cardiac function tests to assess long-term prognosis. At present, electrocardiograms (ECGs) are normal in six patients. However, all eight patients had a prolonged preejection period (PEP) to left ventricular ejection time (LVET) ratio 30 s after amylnitrate (AN) inhalation. Six patients had perfusion defects by exercise thallium-201 myocardial scintigraphy, and two patients developed ST segment depression in treadmill exercise testing. These patients are symptom-free even though their physical activity has not been restricted. Yet they proved to have serious abnormalities suggesting sequelae of myocardial infarction or existing myocardial ischemia. Judging from the results of noninvasive cardiac function tests and recently performed coronary angiography, five of the eight patients require coronary bypass surgery.

Adolescent↗
PubMed1991

Coronary sinus blood flow and coronary haemodynamic function in children: measurement by the continuous thermodilution method with coronary sinus cannulation via the femoral vein.

In 19 children with Kawasaki disease without any cardiac sequelae the coronary sinus was cannulated via the femoral vein with a specially designed flow catheter and coronary sinus blood flow was measured by the continuous thermodilution method. There was a statistically significant positive correlation between coronary sinus blood flow and age, body surface area, and left ventricular mass, but coronary sinus blood flow per left ventricular mass (100 g) was negatively correlated with age, body surface area, and left ventricular mass. Coronary vascular resistance was negatively correlated with age, body surface area, and left ventricular mass. Younger children require a much greater coronary blood flow per left ventricular mass and have a higher coronary vascular resistance than older children and adolescents. These results may indicate that coronary blood flow is less efficient in childhood than in adolescence or adulthood.

Adolescent↗
PubMed1991

[Exercise and dipyridamole-loading in evaluation of ischemic coronary lesion and coronary reserve in children with Kawasaki disease].

In order to compare the clinical effects of exercise-loading and intravenous dipyridamole-loading tests in evaluating ischemic coronary lesion and coronary reserve, we evaluated changes in ECG, 201-Tl scintigraphy, coronary flow and myocardial metabolism in 10 patients with Kawasaki disease (age range: 7-16 years). Although both loading tests affect coronary hemodynamics and myocardial metabolism by different mechanisms, both were equally effective in detecting ischemic coronary lesion and reduced coronary reserve. On the other hand, when considered on the basis of clinical examination methods used, the dipyridamole-loading test was more effective for evaluating clinical symptoms and ECG, while exercise-loading was more effective for evaluating 201Tl scintigraphy and supply-demand balance. These results suggest that, in the evaluation of ischemic coronary lesion, assessment of clinical effects by a combination of several examination methods is required.

Adolescent↗
PubMed1991

[Evaluation of coronary hemodynamics and coronary reserve in children with coronary sequelae of Kawasaki disease].

We measured coronary blood flow by the continuous thermodilution method during coronary sinus catheterization via the femoral vein, and evaluated coronary reserve based on the findings of coronary hemodynamics and myocardial metabolism during atrial pacing. The study subjects consisted of 31 pediatric cases with a history of Kawasaki disease. Among them, 19 had normal coronary angiograms (Group A), 8 had dilated coronary lesions (Group B), and 4 had stenotic coronary lesions (Group C) on selective left coronary angiograms. 1. Coronary blood flow at rest: There were no significant differences between Groups A and B. In Group C, slightly low values were obtained in 2 patients with obstruction or recanalization in the left anterior descending artery. 2. Rate of an increase in coronary blood flow during atrial pacing: It was significantly lower in 5 of 19 patients in Group A, in 2 of 8 in Group B, and in one of 4 in Group C. However, in 2 patients with lower coronary blood flow at rest, the rate of an increase in coronary blood flow during atrial pacing was higher. 3. Following atrial pacing, enhanced anaerobic metabolism was observed in 6 of 17 patients (Group A, 2 of 5; Group B, 2 of 8; Group C, 2 of 4) who showed a poor increase in coronary blood flow during atrial pacing. These results indicate that coronary reserve may decrease even in patients without any coronary sequelae of Kawasaki disease on selective coronary angiograms possibly because of inadequate imaging of the microcirculation, i.e., the problem of the pathologic process at the level of small intramyocardial arterioles. To investigate the coronary sequelae of Kawasaki disease, the evaluation of coronary hemodynamics and myocardial metabolism by coronary sinus catheterization before and after atrial pacing is highly recommended.

Adolescent↗
PubMed1991

[Effects of isosorbide dinitrate on coronary and systemic circulation in children].

The effects of isosorbide dinitrate (ISDN) on the coronary and systemic circulation were evaluated in 8 children with angiographically normal coronary arteries. ISDN, 100 micrograms/kg, was given as a intracoronary injection. The pulmonary artery pressure, pulmonary capillary wedge pressure and left ventricular end diastolic pressure which are related to the pre-load were significantly reduced 1 min after the ISDN injection. The systolic blood pressure was reduced, and heart rate increased. The cardiac output, pressure-rate product and systemic vascular resistance showed no significant change. The systolic work index, however, was significantly reduced. ISDN induced a significant dilatation, ranging from 4.0% to 12.9%, in the diameter of the coronary vessels. There was, however, no change in the coronary blood flow, coronary perfusion pressure and coronary vascular resistance. The grade of the dilatation of the coronary vessels by ISDN in children was lower as compared with that in adult.

Adolescent↗
PubMed1990

Atrial septal aneurysm in infancy.

Thirteen infants were found to have atrial septal aneurysms (ASAs) on two-dimensional (2D) echocardiography and their characteristics and natural course have been studied by 2D Doppler echocardiography. Atrial septal aneurysm was accompanied by atrial septal defect (ASD) or other cardiac malformations in 12 of 13 patients, and as an isolated anomaly in one patient. Spontaneous closure of ASD by aneurysmal formation of the interatrial septum was observed in 10 patients. The aneurysms of all 13 patients showed a moderate reduction in size, 14 to 25 months (mean 18 months), after these aneurysms had been first diagnosed and 10 subsequently disappeared. It is likely that ASA occurring in infancy will develop in patients with spontaneous closure of an ASD, and that such an aneurysm has a tendency to regress as the patient grows up.

Echocardiography, Doppler↗
PubMed1989

A case of total left anomalous pulmonary venous connection with intact atrial septum diagnosed by two-dimensional and Doppler echocardiography.

Unilateral total anomalous pulmonary venous connection from a unilateral lung is extremely rare. A 6-year-old patient with anomalous pulmonary venous connection from the entire left lung to the left innominate vein, with an intact atrial septum, diagnosed by two-dimensional and Doppler echocardiography is reported. The combination of two-dimensional and Doppler echocardiography is very useful not only for anatomical diagnosis, but also for evaluation of its hemodynamics, despite the wide anatomical variability of the pulmonary venous connection. This is the first report of a case of left total anomalous pulmonary venous connection diagnosed noninvasively.

Brachiocephalic Veins↗
PubMed1989

[The supracardiac type of total anomalous pulmonary venous return in a ten-day-old neonate: report of a successfully treated case].

A case of a ten-day-old neonate weighing 3,867 g with the supracardiac type of total anomalous pulmonary venous return (TAPVR) is reported. The preoperative diagnosis was determined mainly by digital subtraction angiography. Surgical correction was carried out in this patient as an emergency operation. Under cardiopulmonary bypass on beating which required 3 hours and 7 minutes, anastomosis between the common pulmonary vein and the left atrium, ligation of both the anomalous vertical vein and the persistent ductus arteriosus, and closure of the atrial septal defects were successfully performed. Postoperatively cardiac failure was markedly improved, although 5 days were required for the weaning from the artificial respirator. The angiographic and hemodynamic examinations showed a complete repair of TAPVR. At present, 2 months after the operation, the patient shows an average development.

Female↗
PubMed1988

QS pattern in the right precordial leads of a child with extensive myocardial fibrosis following myocarditis.

A QS pattern in the right precordial leads of the electrocardiogram was noted in a 9-year-old asymptomatic boy. Echocardiography revealed paradoxical movement of the interventricular septum, which showed interstitial myocardial fibrosis in the biopsy specimen and a defective uptake of thallium-201. Extensive myocardial fibrosis was probably a sequela of an attack of myocarditis in infancy.

Child↗